Key words: supercritical water, hydrocarbons, oxidation, thermal and chainthermal explosion
The kinetics and mechanism of eicosane, benzene, naphthalene and bitumen (the residuum
of petroleum vacuum distillation) oxidation after injection in a cylindrical reactor
with Н2О/О2 mixture under supercritical conditions are investigated. The initial values
of temperature and pressure varied in the ranges of 390÷430 °C, 26,7÷38,7 MPa,
respectively. Concentrations of reagents in the starting mixtures were (in mol/dm3)
up to 0,92 (oxygen), 0,52 (eicosane), 0,36 (benzene), 0,15 (naphthalene), 0,17 (bitumen — per one hypothetical C10H14.3 molecule), and 7÷20 (water). For all substances explosive
oxidation was observed. The global kinetic equations for heat generation rate at thermal
oxidation of С6Н6 , C10H8 and bitumen were received. The duration of pressure jump
at C20H42 oxidation did not exceed 10 ms which does not allow to describe the process
kinetics and mechanism. For С6Н6 at low concentration of water the consecutive
change of oxidation mechanisms from thermal to low-temperature and than — to
high-temperature chain-thermal ones was found. Apparent activation energies of lowtemperature
and high-temperature explosive oxidation of С6Н6 are equal to 80±7 and
349 ±30 kJ/mol, correspondingly.